COVID-19 pneumonia imaging follow-up: when and how? A proposition from ESTI and ESR.

This document from the European Society of Thoracic Imaging (ESTI) and the European Society of Radiology (ESR) discusses the role of imaging in the long-term follow-up of COVID-19 patients, to define which patients may benefit from imaging, and what imaging modalities and protocols should be used. Insights into imaging features encountered on computed tomography (CT) scans and potential pitfalls are discussed and possible areas for future review and research are also included. KEY POINTS: • Post-COVID-19 pneumonia changes are mainly consistent with prior organizing pneumonia and are likely to disappear within 12 months of recovery from the acute infection in the majority of patients. • At present, with the longest series of follow-up examinations reported not exceeding 12 months, the development of persistent or progressive fibrosis in at least some individuals cannot yet be excluded. • Residual ground glass opacification may be associated with persisting bronchial dilatation and distortion, and might be termed "fibrotic-like changes" probably consistent with prior organizing pneumonia.

Milestones towards lung cancer screening implementation.

The European Society of Radiology (ESR) and European Respiratory Society (ERS) published their joint statement paper on lung cancer screening (LCS), on 12 February 2020. This document joins and completes previous recommendations on LCS with specific emphasis on the analysis of issues encountered in the practical implementation of LCS in the community. Major milestones to enable the most efficient and equal dissemination of LCS are recognised as engagement of all stakeholders (e.g. candidate/participant, general practitioners, up to the specialised LCS facility), quality assurance, and primary prevention in the form of provision of counselling for smoking cessation.

DIPNECH: when to suggest this diagnosis on CT.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is an under-recognized disease characterized by proliferation of neuroendocrine cells in the bronchial wall. It is considered a pre-invasive lesion for lung carcinoid tumours and is found in 5.4% of patients undergoing surgical resection for lung carcinoid tumours. Other manifestations of DIPNECH include bronchial obstruction and formation of tumorlets. DIPNECH preferentially affects middle-aged women. Patients are either asymptomatic or present with long-standing dyspnoea due to obstructive syndrome that can be mistaken for asthma. At CT, mosaic attenuation with multiple small nodules is very suggestive of DIPNECH. The aim of this review is to describe DIPNECH-related CT features and correlate them with histology, in order to help radiologists suggest this diagnosis and distinguish DIPNECH from other causes of mosaic perfusion.

Thoracic endometriosis syndrome: CT and MRI features.

Thoracic endometriosis is considered to be rare, but is the most frequent form of extra-abdominopelvic endometriosis. Thoracic endometriosis syndrome affects women of reproductive age. Diagnosis is mainly based on clinical findings, which can include catamenial pneumothorax and haemothorax, non-catamenial endometriosis-related pneumothorax, catamenial haemoptysis, lung nodules, and isolated catamenial chest pain. Symptoms are typically cyclical and recurrent, with a right-sided predominance. Computed tomography (CT) is the first-line imaging method, but is poorly specific; therefore, its main role is to rule out other pulmonary diseases. However, in women with a typical clinical history, some key CT findings may help to confirm this often under-diagnosed syndrome. MRI can also assist with the diagnosis, by showing signal changes typical of haemorrhage within diaphragmatic or pleural lesions.

From randomized trials to the clinic: is it time to implement individual lung-cancer screening in clinical practice? A multidisciplinary statement from French experts on behalf of the French intergroup (IFCT) and the groupe d'Oncologie de langue francaise (GOLF).

BACKGROUND: Despite advances in cancer therapy, mortality is still high except in early-stage tumors, and screening remains a challenge. The randomized National Lung Screening Trial (NLST), comparing annual low-dose computed tomography (LDCT) and chest X-rays, revealed a 20% decrease in lung-cancer-specific mortality. These results raised numerous questions. The French intergroup for thoracic oncology and the French-speaking oncology group convened an expert group to provide a coherent outlook on screening modalities in France. METHODS: A literature review was carried out and transmitted to the expert group, which was divided into three workshops to tackle specific questions, with responses presented in a plenary session. A writing committee drafted this article. RESULTS: The multidisciplinary group favored individual screening in France, when carried out as outlined in this article and after informing subjects of the benefits and risks. The target population involves subjects aged 55-74 years, who are smokers or have a 30 pack-year smoking history. Subjects should be informed about the benefits of quitting. Screening should involve LDCT scanning with specific modalities. Criteria for CT positivity and management algorithms for positive examinations are given. CONCLUSIONS: Individual screening requires rigorous assessment and precise research in order to potentially develop a lung-cancer screening policy.

A credible homogenized finite element model to predict radius fracture in the case of a forward fall.

Fragility fractures that occur after a fall from a standing height or less are almost always due to osteoporosis, which remains underdiagnosed and untreated. Patient-specific finite element (FE) models have been introduced to predict bone strength and strain. This approach, based on structure mechanics, is derived from Quantitative Computed Tomography (QCT), and element mechanical properties are computed from bone mineral densities. In this study, we developed a credible finite element model of the radius to discriminate low-trauma-fractured radii from non-fractured radii obtained experimentally. Thirty cadaveric radii were impacted with the same loading condition at 2 m/s, and experimental surface strain was retrieved by stereo-correlation in addition to failure loads in fracture cases. Finite element models of the distal radius were created from clinical computed tomography. Different density-elasticity relationships and failure criteria were tested. The strongest agreement (simulations-experiments) for average strain showed a Spearman's rank correlation (ρ) between 0.75 and 0.82, p < 0.0001, with a root mean square error between 0.14 and 0.19%. The experimental mean strain was 0.55%. Predicted failure load error (23%) was minimized for derived Pistoia's failure criterion. Numerical failure demonstrated area under the receiver operating characteristic (ROC) curves of 0.76 when classifying radius fractures with an accuracy of 82%. These results suggest that a credible FE modelling method in a large region of interest (distal radius) is a suitable technique to predict radius fractures after a forward fall.

Influence of loading conditions in finite element analysis assessed by HR-pQCT on ex vivo fracture prediction.

Many fractures occur in individuals with normal areal Bone Mineral Density (aBMD) measured by Dual X-ray Absorptiometry (DXA). High Resolution peripheral Quantitative Computed Tomography (HR-pQCT) allows for non-invasive evaluation of bone stiffness and strength through micro finite element (µFE) analysis at the tibia and radius. These µFE outcomes are strongly associated with fragility fractures but do not provide clear enhancement compared with DXA measurements. The objective of this study was to establish whether a change in loading conditions in standard µFE analysis assessed by HR-pQCT enhance the discrimination of low-trauma fractured radii (n = 11) from non-fractured radii (n = 16) obtained experimentally throughout a mechanical test reproducing a forward fall. Micro finite element models were created using HR-pQCT images, and linear analyses were performed using four different types of loading conditions (axial, non-axial with two orientations and torsion). No significant differences were found between the failure load assessed with the axial and non-axial models. The different loading conditions tested presented the same area under the receiver operating characteristic (ROC) curves of 0.79 when classifying radius fractures with an accuracy of 81.5%. In comparison, the area under the curve (AUC) is 0.77 from DXA-derived ultra-distal aBMD of the forearm with an accuracy of 85.2%. These results suggest that the restricted HR-pQCT scanned region seems not sensitive to loading conditions for the prediction of radius fracture risk based on ex vivo experiments (n = 27).

Impact of digital ulcers on disability and health-related quality of life in systemic sclerosis.

OBJECTIVE: To assess the impact of digital ulcers (DUs) on disability and health-related quality of life (HRQoL) in systemic sclerosis (SSc). METHODS: Two hundred and thirteen patients with SSc were evaluated at four annual meetings of a patient society between 2004 and 2007 (n = 177) or during hospital stay (n = 36). HRQoL was assessed by the SF-36, global disability by the health assessment questionnaire (HAQ), hand disability by the Cochin Hand Function Scale (CHFS) and global hand and wrist mobility by the Kapandji index. RESULTS: Sixty-seven patients (31.4%) had at least one DU at the time of evaluation. Patients with DUs showed significantly more pitting scars (p<0.001) and calcinosis (p<0.0001) than others. Patients with DU had significantly greater HAQ (mean (SD) 1.218 (0.723) vs 0.930 (0.717), p = 0.008), CHFS (mean (SD) 27.38 (20.68) vs 16.73 (18.19), p<0.0001) and aesthetic prejudice (mean (SD) 6.1 (2.2) vs 3.9 (2.5), p<0.0001) scores than others. Hand and wrist mobility were significantly diminished in patients with DU (mean (SD) Kapandji score 75.3 (22.8) vs 81.7 (19.2), p<0.0001). The presence of a DU did not significantly alter the physical component but influenced the mental component (mean (SD) 43.38 (12.53) vs 39.58 (9.54), p = 0.026) of the SF36. CONCLUSION: Patients with SSc with DUs have reduced wrist and hand mobility, increased global and hand disabilities and decreased mental component of HRQoL.

Radiological assessment after stereotactic body radiation of lung tumours.

The increasing use of stereotactic body radiation therapy for lung tumours comes along with new post-therapeutic imaging findings that should be known by physicians involved in patient follow-up. Radiation-induced lung injury is much more frequent than after conventional radiation therapy, it can also be delayed and has a different radiological presentation. Radiation-induced lung injury after stereotactic body radiation therapy involves the lung parenchyma surrounding the target tumour and appears as a dynamic process continuing for years after completion of the treatment. Thus, the radiological pattern and the severity of radiation-induced lung injury are prone to changes during follow-up, which can make it difficult to differentiate from local recurrence. Contrary to radiation-induced lung injury, local recurrence after stereotactic body radiation therapy is rare. Other complications mainly depend on tumour location and include airway complications, rib fractures and organizing pneumonia. The aim of this article is to provide a wide overview of radiological changes occurring after SBRT for lung tumours. Awareness of changes following stereotactic body radiation therapy should help avoiding unnecessary interventions for pseudo tumoral presentations.

Optimization of acquisition parameters for reduced-dose thoracic CT: A phantom study.

PURPOSE: The purpose of this study was to analyze the impact of different options for reduced-dose computed tomography (CT) on image noise and visibility of pulmonary structures in order to define the best choice of parameters when performing ultra-low dose acquisitions of the chest in clinical routine. MATERIALS AND METHODS: Using an anthropomorphic chest phantom, CT images were acquired at four defined low dose levels (computed tomography dose index [CTDIvol]=0.15, 0.20, 0.30 and 0.40mGy), by changing tube voltage, pitch factor, or rotation time and adapting tube current to reach the predefined CTDIvol-values. Images were reconstructed using two different levels of iteration (adaptive statistical iterative reconstruction [ASIR®]-v70% and ASIR®-v100%). Signal-to-noise ratio (SNR) as well as contrast-to-noise ratio (CNR) was calculated. Visibility of pulmonary structures (bronchi/vessels) were assessed by two readers on a 5-point-Likert scale. RESULTS: Best visual image assessments and CNR/SNR were obtained with high tube voltage, while lowest scores were reached with lower pitch factor followed by high tube current. Protocols favoring lower pitch factor resulted in decreased visibility of bronchi/vessels, especially in the periphery. Decreasing radiation dose from 0.40 to 0.30mGy was not associated with a significant decrease in visual scores (P<0.05), however decreasing radiation dose from 0.30mGy to 0.15mGy was associated with a lower visibility of most of the evaluated structures (P<0.001). While image noise could be significantly reduced when ASIR®-v100% instead of ASIR®-v70% was used, the visibility-scores of pulmonary structures did not change significantly. CONCLUSION: Favoring high tube voltage is the best option for reduced-dose protocols. A decrease of SNR and CNR does not necessarily go along with reduced visibility of pulmonary structures.

COVID-19 pneumonia: A review of typical CT findings and differential diagnosis.

The standard of reference for confirming COVID-19 relies on microbiological tests such as real-time polymerase chain reaction (RT-PCR) or sequencing. However, these tests might not be available in an emergency setting. Computed tomography (CT) can be used as an important complement for the diagnosis of COVID-19 pneumonia in the current epidemic context. In this review, we present the typical CT features of COVID-19 pneumonia and discuss the main differential diagnosis.

Nodular reverse halo sign in active pulmonary tuberculosis: A rare CT feature?

PURPOSE: The purpose of this study was to investigate the prevalence of the nodular reverse halo sign (NRHS) in chest computed tomography (CT) in patients with active pulmonary tuberculosis. MATERIALS AND METHODS: From March 2018 to March 2019, 29 consecutive patients with a culture-confirmed active pulmonary tuberculosis and who underwent chest CT examination during hospital-admission were retrospectively included in the study. There were 24 men and 5 women with a mean age of 40.9±16.7 (SD) years (range: 18-80years). Chest CT examinations of included patients were evaluated for the presence of NRHS and other tuberculosis-related CT signs. RESULTS: CT revealed the NRHS in 5 patients (5/29; 17%). The other CT signs of tuberculosis included consolidations in 18 patients (18/29; 62%), tree-in-bud pattern in 14 patients (14/29; 48%), cavitation in 12 patients (12/29; 41%), sparse nodules in 10 patients (10/29; 34%), and pleural effusion in 8 patients (8/29; 28%). CONCLUSION: CT shows NRHS in 17% of patients with active pulmonary tuberculosis, indicating that the sign is not as rare as previously thought in patients with this condition.

Incidental diagnosis of Covid-19 pneumonia on chest computed tomography.

PURPOSE: The purpose of this study was to determine the prevalence and imaging characteristics of incidentally diagnosed COVID-19 pneumonia on computed tomography (CT). MATERIALS AND METHODS: This retrospective study was conducted between March 20th and March 31st, 2020 at Cochin hospital, Paris France. Thoracic CT examinations of all patients referred for another reason than a suspicion of SARS-CoV-2 infection were reviewed. CT images were analyzed by a chest radiologist to confirm the presence of findings consistent with COVID-19 pneumonia and quantify disease extent. Clinical and biological data (C-reactive protein serum level [CRP] and white blood cell count) of patients with CT findings suggestive for COVID-19 pneumonia were retrieved from the electronic medical chart. RESULTS: During the study period, among 205 diagnostic CT examinations, six examinations (6/205, 3%) in 6 different patients (4 men, 2 women; median age, 57 years) revealed images highly suggestive of COVID-19 pneumonia. The final diagnosis was confirmed by RT-PCR. Three inpatients were suspected of extra thoracic infection whereas three outpatients were either fully asymptomatic or presented with fatigue only. All had increased CRP serum level and lymphopenia. Disease extent on CT was mild to moderate in 5/6 patients (83%) and severe in 1/6 patient (17%). CONCLUSION: Cumulative incidence of fortuitous diagnosis if COVID-19 pneumonia did not exceed 3% during the highest pandemic phase and was predominantly associated with limited lung involvement.

Cumulative radiation dose after lung transplantation in patients with cystic fibrosis.

PURPOSE: The purpose of this study was first to evaluate the imaging-related cumulative post-transplantation radiation dose in cystic fibrosis (CF) lung transplantation (LT) recipients and second, to identify the occurrence and type of malignancies observed after LT. MATERIALS AND METHODS: A total of 52 patients with CF who underwent LT at our institution between January 2001 and December 2006 with at least 3 years of survival were retrospectively included. There were 27 men and 25 women with a mean age of 24.4±9.2 (SD) years (range: 7.6-52.9 years) at the time of LT. Calculation of cumulative effective and organ doses after LT were based on dosimetry information and acquisition parameters of each examination. Cumulative radiation doses were calculated until June 2016, but stopped at the time of de novomalignancy diagnosis, for patients developing the condition. RESULTS: Patients received a mean cumulative effective dose of 110.0±51.6 (SD) mSv (range: 13-261.3 mSv) over a mean follow-up of 8.1±3.6 (SD) years (range: 0.5-13.5 years), with more than 100mSv in 5 years in 19/52 patients (37%). Chest CT accounted for 73% of the cumulative effective dose. Mean doses to the lung, breast and thyroid were 152.8±61.1 (SD) mGy (range: 21.2-331.6 mGy), 106.5±43.2 (SD) mGy (range: 11.9-221.4 mGy) and 72.7±31.8 (SD) mGy (range: 9.5-165.0 mGy), respectively. Nine out of 52 patients (17%) developed a total of 10 de novo malignancies, all but one attributable to immunosuppression after a mean post-transplantation follow-up period of 11.1±3.5 (SD) years (range: 3.7-16.3 years). Six-month cumulative effective dose was not greater in patients with de novomalignancies than in those without de novomalignancies (28.9±14.5 (SD) mGy (range: 13.0-53.4) vs 25.6±15.3 (range: 5.0-69.7), respectively, P>0.05). CONCLUSION: The cumulative effective dose exceeded 100 mSv in 5 years in 37% of LT recipients, the reason why continuous efforts should be made to optimize chest CT acquisitions accounting for 73% of the radiation dose.

Combined pulmonary fibrosis and emphysema in systemic sclerosis: A syndrome associated with heavy morbidity and mortality.

BACKGROUND: The syndrome of combined pulmonary fibrosis and emphysema (CPFE) primarily due to tobacco smoking has been reported in connective tissue disease, but little is known about its characteristics in systemic sclerosis (SSc). METHODS: In this retrospective multi-center case-control study, we identified 36 SSc patients with CPFE, and compared them with 72 SSc controls with interstitial lung disease (ILD) without emphysema. RESULTS: Rate of CPFE in SSc patients with CT scan was 3.6%, and 7.6% among SSc patients with ILD. CPFE-SSc patients were more likely to be male (75 % vs 18%, p < 0.0001), smokers (83 % vs 33%, p < 0.0001), and to have limited cutaneous SSc (53 % vs 24% p < 0.01) than ILD-SSc controls. No specific autoantibody was significantly associated with CPFE. At diagnosis, CPFE-SSc patients had a greater decrease in carbon monoxide diffusing capacity (DLCO 39 ± 13 % vs 51 ± 12% of predicted value, p < 0.0001) when compared to SSc-ILD controls, whereas lung volumes (total lung capacity and forced vital capacity) were similar. During follow-up, CPFE-SSc patients more frequently developed precapillary pulmonary hypertension (PH) (44 % vs 11%, p < 10-4), experienced more frequent unscheduled hospitalizations (50 % vs 25%, p < 0.01), and had decreased survival (p < 0.02 by Kaplan-Meier survival analysis) as compared to ILD-SSc controls. CONCLUSIONS: The CPFE syndrome is a distinct pulmonary manifestation in SSc, with higher morbidity and mortality. Early diagnosis of CPFE by chest CT in SSc patients (especially smokers) may result in earlier smoking cessation, screening for PH, and appropriate management.

Disability and quality of life of patients with knee or hip osteoarthritis in the primary care setting and factors associated with general practitioners' indication for prosthetic replacement within 1 year.

OBJECTIVE: To assess disability and health-related quality of life (HRQoL) of patients with knee or hip OA in primary care and to determine factors associated with GPs' opinion that their patients will need prosthetic replacement within 1 year after the consultation. DESIGN: A cross-sectional national survey. SETTING: Primary care in France. PARTICIPANTS: 1471 GPs and 4183 patients with hip or knee OA. MEASURES: Pain on an 11-point numeric scale (0-10), disability on the Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC) (1-100) and Lequesne index (0-24), and quality of life on the Medical Outcomes Study 36-item Short Form (MOS SF-36; 0-100). RESULTS: We analyzed records of 4121 patients (2540 knee, 1581 hip OA). Patients with knee or hip OA exhibited high and similar levels of pain (5.2+/-2.1 and 5.3+/-2.3) and disability (Lequesne score: 12.0+/-4.2 and 11.8+/-4.3; WOMAC score: 45.7+/-19.3 and 45.2+/-17.3) The decrease in HRQoL was similar for patients with either location of the disease. GPs more often considered that their patients with hip OA would need prosthetic replacement within 1 year (28.1%) than those with knee OA (15.8%). Most factors associated with GPs' opinion were identified for both locations of disease and were related to disability and pain levels. CONCLUSIONS: In the primary care setting, patients with knee or hip OA have similar, high disability levels and substantially low HRQoL. Patients' disability seems to play a central role in GPs' opinion of the need for their patients with either type of OA to undergo prosthetic replacement within 1 year.

[What is the interest of early knee mobilization after total knee arthoplasty?]. / Intérêt d'une mobilisation très précoce après la pose d'une prothèse totale de genou? Elaboration de recommandations françaises pour la pratique clinique.

AIMS: To develop clinical practice guidelines for early mobilisation after total knee replacement (TKR). METHOD: We used the French Society of Physical and Rehabilitation Medicine (SOFMER) methodology, which associates a systematic review of the literature, collection of information regarding current clinical practice and external review by a multidisciplinary expert panel. RESULTS: A review of the literature and French clinical practice allow for recommending early mobilisation, at day 0, after TKR. This practice, with continuous passive motion, does not seem to increase the frequency of complications and seems to help with rapid recovery of the joint range of motion. Trials with good methodology must be developed to define the criteria for prescribing early mobilisation after TKR. These trials should focus mainly on joint range of motion but also on economical criteria (duration of hospitalisation, rehabilitation, physiotherapy, use of painkillers) and the satisfaction of the patient.

[What is the interest of early mobilization after total hip arthroplasty? Development of French guidelines for clinical practice]. / Intérêt d'une mobilisation très précoce après la pose d'une prothèse totale de hanche ? Elaboration de recommandations françaises pour la pratique clinique.

AIMS: To develop clinical practice guidelines for early mobilisation after total hip replacement (THR). METHOD: We used the French Society of Physical and Rehabilitation Medicine (Sofmer) methodology, which associates a systematic review of the literature, the collection of information regarding current clinical practice and external review by a multidisciplinary expert panel. RESULTS: Recommending early mobilisation after THR is not established by a review of the literature. A survey of French clinical practice allows for recommending early mobilisation in the context of complex hip issues. Trials with good methodology must be developed to evaluate the interest of early functional mobilisation corresponding to when patients first stand and take their first steps after surgery. These trials should focus mainly on the final pain, functional status, and reduction of handicap.

[Bronchiectasis imaging]. / Imagerie des dilatations des bronches.

Bronchiectasis are defined as an irreversible focal or diffuse dilatation of the bronchi and can be associated with significant morbidity. The prevalence is currently increasing, probably due to an increased use of thoracic computed tomography (CT). Indeed, the diagnosis relies on imaging and chest CT is the gold standard technique. The main diagnosis criterion is an increased bronchial diameter as compared to that of the companion artery. However, false positives are possible when the artery diameter is decreased, which is called pseudo-bronchiectasis. Other features such as the lack of bronchial tapering, and visibility of bronchi within 1cm of the pleural surface are also diagnostic criteria, and other CT features of bronchial disease are commonly seen. Thoracic imaging also allows severity assessment and long-term monitoring of structural abnormalities. The distribution pattern and the presence of associated findings on chest CT help identifying specific causes of bronchiectasis. Lung MRI and ultra-low dose CT and are promising imaging modalities that may play a role in the future. The objectives of this review are to describe imaging features for the diagnosis and severity assessment of bronchiectasis, to review findings suggesting the cause of bronchiectasis, and to present the new developments in bronchiectasis imaging.